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The Metabolizable Energy Content of Rapeseed Oils and Rapeseed Oil Foots and the Effect of Blending with Other Fats
143
MAREK'S DISEASE IN QUAIL REFERENCES Andrewes, C. H., and R. E. Glover, 1939. A case of neurolymphomatosis in turkey. Vet. Rec. S I : 934. Halliwell, W. H., 1971. Lesions of Marek's disease in a Great Horned Owl. Avian Dis. 15: 49-55. Jungherr, E., 1939. Neurolymphomatosis Phasianorum. J. Amer. Vet. Med. Assn. 94: 49. Papenheimer, M., L. C. Dunn and V. Cone, 1929. Studies on fowl paralysis (Neurolymphomatosis
Gallinarum). Exp. Med. 49: 63-85. Payne, L. N., and P. M. Biggs, 1967. Studies on Marek's disease. II. Pathogenesis. Nat. Cancer Inst. 39: 281-291. Sevoian, M., D. M. Chamberlain, and R. N. Larose, 1963. Avian lymphomatosis. VII. New support for etiologic unity. Proc. Seventeenth Worlds Vet. Cong. 2: 1475. Wight, P. A. L., 1963. Lymphoid leucosis and fowl paralysis in the quail. Vet. Rec. 75: 685-687.
S. P. LALL AND S. J. SLINGER Department of Nutrition, University of Guelph, Guelph, Ontario, Canada (Received for publication April 12, 1972)
ABSTRACT Experiments were carried out with chicks and turkey poults to determine the metabolizable energy content of rapeseed oils and rapeseed oil foots and the effect on energy utilization of blending these oils with tallow and mixtures of saturated fatty acids. In general, low erucic acid rapeseed oil (Oro variety) gave superior growth and feed efficiency and was as high or higher in M.E. value as compared with regular Brassica campestris rapeseed oil. While rapeseed oils and rapeseed oil foots were reasonably well utilized as a source of energy by chicks and poults, there was a synergistic effect in energy utilization when these oils were mixed with tallow. Thus the energy content of the mixture of rapeseed oil and tallow was greater than that anticipated from the fats fed singly. The synergism was less for poults than for chicks, probably because poults utilized rapeseed oils to a greater extent than chicks when fed without mixing. Chicks fed mixtures made up chiefly of palmitic and stearic acids, along with rapeseed oil or rapeseed foots, demonstrated similar synergism in fat utilization to those fed tallow with rapeseed oil. These results confirm and extend previous findings indicating that rapeseed oil is imbalanced in fatty acid make-up for maximum absorption, being too low in the long chain saturated fatty acids, palmitic and stearic. While synergism in energy utilization was also demonstrated when low erucic acid oil was mixed with tallow, the effect was less than with regular Brassica campestris oil. This is probably explained by the fact that the low erucic acid oil is better utilized when fed alone than the regular rapeseed oil. POULTRY SCIENCE 52:
INTRODUCTION
Q
UANTITATIVE data on the utilization of rapeseed oil (RSO) by poultry ate quite limited. Joshi and Sell (1964) reported that inclusion of 5 or 10% RSO in the diet of turkey poults caused a depression in weight gain and feed consumption with the magnitude of depression being in direct proportion to the RSO content of the diet. Metabolizable energy (M.E.) values determined on the total diets indicated that
143-151,
1973
the energy supplied by RSO was as available to poults as that from soybean oil (SBO), sunflower oil or animal tallow. Salmon (1969a) reported that 9% RSO depressed the growth, feed conversion, and dietary M.E. of diets for growing turkeys as compared to 9% SBO; mixtures of RSO with one-third or more of SBO or with less than one-third beef tallow gave equal performance to 9% SBO. However, Blakely et d. (1965) found that 6 or 10% RSO was
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The Metabolizable Energy Content of Rapeseed Oils and Rapeseed Oil Foots and the Effect of Blending with Other Fats
144
S. P. LALL AND S. J. SLINGER
ported for erucic acid, the utilization of low erucic acid RSO (LEAR) was also studied. In view of the findings of Sibbald etal. (1961,1962) andArtman (1964) that mixing SBO and tallow resulted in a greater M.E. than predicted from the arithmetic mean of the two fats fed singly, the present studies were also designed to test the synergistic relationship between tallow and rapeseed oil. Estimates of the M.E. of RSO in previous studies reported in the literature have been based on determining the M.E. of complete diets containing RSO or other oils. While this method permits a rough approximation of the M.E. of RSO as compared to certain other oils it does not permit as accurate an estimate as the quantitative method used here. EXPERIMENTAL MATERIALS AND METHODS
A series of four experiments was conducted to determine the M.E. value of RSO, RSO foots (acidulated soap stocks), tallow and various mixtures of these fat products and fatty acids. The regular RSO was Brassica campestris and was fed in both the crude and degummed state but without futher refining. The LEAR was Oro variety of the Brassica napus species containing 1.2% erucic acid. For the various experiments, male one-day-old White Rock chicks or female Large White turkeys were housed in electrically heated wire-floored battery brooders. The chicks were given a commercial starting ration for a period of 2 weeks preceeding experiment 1 and 1 week in experiments 3 and 4. Thereafter, the birds were weighed, divided into groups having a weight spread of 5 g. and distributed into pens until each pen contained 10 chicks or 8 poults. All experiments were of randomized complete block design with each of the experimental diets allotted to four replicate pens. The birds were fed a
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not growth depressing for 20-24 week-old finishing turkeys. In contrast to the growth depressing effects of RSO reported for poults, Sell and Hodgson (1962) and Tsang et al. (1962) found no such detrimental effect with the chick. Sell and Hodgson (1962) observed that 4 to 8% RSO was as effective as comparable levels of SBO in improving weight gain and efficiency of feed utilization of chicks. However, Salmon (1969b) reported that substitution of different levels of RSO in diets containing 10% total added oil depressed the growth of chicks but that the M.E. content of the diets was approximately the same. Furthermore, Sheppard et al. (1971) reported that chicks fed diets containing 16% RSO showed reduced growth and poorer feed utilization as compared with chicks receiving diets with 16% corn oil. Based on their method of assay rapeseed oil had 67 and 70% of the energy value of corn oil in two experiments. Work with rats indicates that the relatively poor performance on RSO may be due to an imbalance of saturated and monounsaturated fatty acids (Hopkins et al., 1955; Murray et al., 1958) or the relatively low content of palmitic acid (Beare et al., 1963; Craig et al, 1963a, b) in rapeseed oil. Renner and Hill (1961) and Young (1961) showed that palmitic and stearic acids were poorly utilized by chicks when fed alone; however, the absorption was much more rapid when these fatty acids were fed as part of a mixture of fatty acids. Young and Garrett (1963) reported that the presence of oleic acid and to some extent linoleic acid enhanced the absorption of saturated fatty acids. The following studies were undertaken to determine the M.E. content of RSO and rapeseed oil foots (acidulated soap stocks from RSO) for chicks and turkey poults. The same samples were used for both species. Because of the deleterious effects re-
145
METABOLIZABLE ENERGY OF RAPESEED OILS
RESULTS AND DISCUSSION
Experiment 1. The first experiment was
TABLE 1.—Composition of basal diets Basal diets 1 Ingredient
• Chickens
Turkeys
(%)
(%)
27.25 Ground corn Soybean meal (49% protein) 56.00 4.00 Dehydrated alfalfa meal (17% protein) 2.50 Meat meal (50% protein) 2.50 Fish meal (60% protein) 2.50 Dried whey (55% lactose) 2.00 Ground limestone 2.00 Dicalcium phosphate 0.50J Iodized salt 0.75 Vitamin-mineral mix 1
26.00 58.50 2.00 2.50 3.50 2.00 2.00 2.25 0.50s 0.75
Each diet contained 0 . 3 % chromium sesquiox-
ide.
8
Vitamin-mineral mix provided (per kg. of basal diet): vitamin A, 10,080 I.U.; vitamin D 3 , 1,240 I.C.U.; vitamin E, 32 I.U.; menadione sodium bisulfite, 2.2 mg.; riboflavin, 7 mg.; d-calcium pantothenate, 6.2 mg.; niacin, 5.5 mg.; vitamin B12, 0.03 mg.; choline chloride, 188 mg.; manganese, 84 mg.; zinc, 84 mg.; 3-nitro-4^hydroxyphenylarsonic acid, 50 mg.; DL-methionine, 500 mg.; penicillin, 11 mg. 5 Vitamin-mineral mix provided (per kg. of basal diet): vitamin A, 10,080 I.U.; vitamin D 3 , 1,500 I.C.U.; vitamin E, 32 I.U.; menadione sodium bisulfite, 3 mg.; riboflavin, 8 mg.; d-calcium pantothenate, 7.5 mg.; niacin, 60 mg.; vitamin Bis, 0.03 mg.; choline chloride, 225 mg.; manganese, 84 mg.; zinc, 84 mg.; 3-nitro-4-hydroxyphenylarsonic acid, 50 mg.; DL-methionine, 500 mg.; penicillin, 11 mg.
designed to determine the M.E. content of degummed RSO, undegummed RSO, LEAR, RSO foots (acidulated soap stocks from RSO), A.V. blend (a commercial mixture of animal and vegetable fat containing some RSO), prime tallow and a 50:50 mixture of tallow and RSO or RSO foots. Because a sufficient amount of LEAR was not available at the time, the M.E. value for the mixture of tallow and the LEAR was not determined. The M.E. values derived for the fats and fat mixtures on chicks, together with the weight gain, feed consumption and feed: gain data, are presented as means in Table 2. Prime tallow contained significantly less M.E. than any of the oils being tested. The M.E. of undegummed RSO was slightly higher than degummed RSO. However,
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practical corn-soybean diet (Table 1, ration A for chicks, ration B for poults) or the appropriate diet containing 20% of the various fats, fat mixtures or fatty acid mixtures. The fat replaced the diet as a whole. The chicks were given the experimental diets to 4 weeks of age. The turkey poults received the experimental diets from dayold through 3 weeks of age. All diets were supplied ad libitum. During the last 6 days of the experiments, three excreta samples were collected on alternate days from each pen, pooled, frozen, lyophilized and ground in preparation for analyses to permit the determination of M.E. values according to the procedure outlined by Sibbald and Slinger (1963). Both feed and excreta samples were assayed for gross energy using a Parr oxygen bomb calorimeter, nitrogen by the method of Kjeldahl (A.O.A.C, 1965) and chromium sesquioxide using a Techtron atomic absorbtion spectrophotometer (Arthur, 1970). The fatty acid composition of the fats was determined by gas-liquid chromatography. A Barber Colman series 5000 gas chromatograph equipped with dual hydrogen flame ion detectors was used. The stainless steel column was 200 cm. X 2 mm. I.D. and was packed with 85% chromosorb W coated with 15% ethylene glycol adipate; they were operated isothermally at 210°C. The determination of total free fatty acids, unsaponifiables and moisture was accomplished by the procedure of the Association of Official Agricultural Chemists (1965). The data from these experiments were analyzed by the method of analysis of variance and the test of significance was made using Duncan's multiple range test at the 5% probability level as outlined by Steel and Torrie (1960).
146
S. P. LALL AND S. J. SLINGER
TABLE 2.—Fat utilization by the chicken1 Metabolizable energy Supplement
Average feed cons.
(g.)
(g.)
323 374d 387M 4H«b
3771*1 367 d 390 b c d 427» 4Q9ab
403»bo 394bcd 8.2 30
Sx DF 1
693" 638cd 658b° 673*b 648b° 634«> 651 bc 657"° 671*b 656b° 626* 7.8 30
Feed/ Gain
Derived
Calculated from components
Increase in M.E.
(kcal./g.)
(kcal./g.)
—
— —• —
(%) —. •— — — — — —
2.15 1.71" 1.70"b 1.64b° 1.72" 1.73" 1.67ab 1.544 1.64b= 1.63b0 1.59°d
7.99 e 7.89* 8:'71d 7.81= 7.86" 7.12 9.18 a b 9.01b° 9.23" 8.97°
0.025 30
0.065 27
•
—
— — —
7.56 7.50 7.46 7.49
21.4 20.1 23.7 19.8
Treatments followed by the same letter are not significantly different (P= <0.05).
weight gain and feed consumption were = 33-34°C.) and well incorporated into somewhat lower for undegummed RSO bile salt conjugated micellar solutions; than degummed RSO. It would appear that however, it was not as well absorbed as rapeseed gums may contain some factor (s) oleic acid. Rocquelin (1969) found that which reduces feed consumption and approximately 75% of the total fatty acids growth but enhances M.E. recovered from feces of rats fed RSO was The M.E. content of LEAR was signifi- erucic acid which was excreted mainly as cantly higher than that of any other fat free acid or partial glycerides. Since the fed singly. Also weight gain and feed effi- metabolizable energy value of a fat is diciency for chicks fed the LEAR were supe- rectly related to absorption, the superior rior to the other fats. Thomasson (1956) performance of chicks fed LEAR supports reported that RSO is more slowly absorbed the view that the lower utilization of reguthan most other oils because of its high lar RSO may be associated with the erucic erucic acid content. It has been shown that acid. oleic acid, which constitutes 6 1 % of LEAR Although RSO foots and A.V. blend gave fatty acids (Table 6) is much better uti- inferior performance based on weight gain lized than erucic acid. Carroll (1965) indi- and feed efficiency, the M.E. values were cated that in rats fed RSO or erucic acid not significantly different from the other the intestinal wall becomes thickened and rapeseed products. the intestinal mucosa takes on a milky apThe M.E. data indicate that mixtures of pearance due to the presence of emulsified various fats with tallow contained more fats, mainly in the form of triglyceride. avilable energy than the mean of the comThis may be due to slow removal from the ponents. The average increase was about intestinal mucosa of glycerides containing 20% (Table 2, last column) and the differerucic acid. ences were statistically significant. CalcuSavary and Constantin (1966) observed lations showed that mixing tallow and the that erucic acid was liquid at 37°C. (M.P. RSO products enhanced the utilization of
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Basal Undegummed RSO Degummed RSO Low erucic RSO RSO foots A.Vt blend Prime tallow (PT) PT+undegummed RSO PT+degummed RSO P T + R S O foots P T + A . V . blend
Average weight gain
METABOLIZABLE ENERGY OF RAPESEED OILS
acids and the low levels of palmitic and stearic acids in this oil. Young (1968) suggested that fat or fat mixtures are more efficiently utilized if the ratio of unsaturated to saturated fatty acids is equal to or greater than 1.4:1. The ratio with the mixture of 50:50 tallow and rapeseed oil was 2.84:1 which is in agreement with the above recommendations. The increase in M.E. upon blending RSO and tallow is greater than that achieved by mixing tallow and soybean oil (Sibbald et al., 1962). It may be that the diluting effect of tallow on the relatively slowly absorbed erucic acid in RSO is another reason for the marked synergism in M.E. when tallow and RSO are blended. Experiment 2. The second experiment was designed to determine the M.E. content of the same samples of RSO and RSO foots used in the previous trial but using turkey poults. The M.E. values (Table 3) indicate that this species made better use of all fats than did chicks. Some of the oils were metabolized to the extent of 100% or more; the undegummed RSO showed an M.E. value of 9.57 vs. a gross energy of 9.45 thus suggesting synergism between the RSO with the fat in the basal diet. Unlike the chicks, the poults receiving the diets containing added fat consumed significantly less feed and gained significantly less weight than the poults fed the basal ration. The fact that tallow resulted in a lowered feed intake and growth in relation to the basal diet suggests that the diets in which the fats were included contained a surplus of energy in relation to protein. The higher M.E. of the RSO products may have exaggerated this imbalance thus accounting for the poorer growth and feed efficiency in the RSO groups as compared with the poults fed tallow. However, the evidence suggests that some of the RSO products, particularly the RSO foots, caused some growth
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the energy in both the tallow and the RSO products in all cases. For example, if it is assumed that the M.E. value of the RSO products do not change when they are combined with tallow it becomes possible to calculate the increase in M.E. attributable to tallow resulting from the blending, viz.: (2 X kcal. M.E./g. mixed fat)—(M.E./g. RSO product) = M.E./g. tallow. Subtracting the M.E. value obtained when tallow was fed alone from the new value indicates the increase in M.E./g. of tallow. Using this calculation, it was found that mixing tallow with degummed RSO resulted in an increase in M.E. content of tallow of 3.01 kcal./g. which would give the tallow an M.E. value of 10.13 kcal./g. However, the gross energy of the tallow was only 9.38 kcal./g. so that mixing of tallow and RSO must have resulted in an increase in energy utilization in both tallow and RSO. The weight gain, feed consumption and feed efficiency data also provided evidence that synergism occurred within the fat mixtures. Since degummed and undegummed RSO both showed a synergistic response, the presence or absence of gums cannot be considered responsible for the increased utilization. Hopkins (1955) proposed that the poor performance of rats fed RSO was due to an imbalance of saturated and monounsaturated fatty acids. The best performance of rats was observed when the ratio of saturated to monounsaturated fatty acids was 1:2. The calculation of this ratio for rapeseed oil was found to have a value of 1:14. The 50:50 mixture of tallow and rapeseed oil approached the desirable level of 1:2. It may well be that in the chick as in the rat the optimum ratio for fat absorption of saturated to monounsaturated fatty acids is of the order of 1:2. The lack of equilibrium between saturated and monounsaturated fatty acids in RSO is not caused solely by the high level of erucic acid but also by the relatively high levels of oleic and eicosenoic
147
148
s. P.
LALL AND S. J . !SLINGER
TABLE 3.—Fat utilization by the turkey1
Metabolizable energy Supplement
Average weight gain
Average feed cons.
(g-)
(g-)
377 212b° 226*bb° 254» 187° 215 b 264> 224»bo 244ab 222ab0 21Sb° 248»b
550 293 b 305 b b 318> 280b 296b 370" 322»b 326 ab 293b 295b 307b
Sx DF
12.8 33
18.4 33
1
Derived
Calculated from components
Increase in M.E.
(kcal./g.)
(kcal./g.)
(%)
— — — — — — —
— — — — — —
b
1.46» 1.38d« 1.35def 1.26e 1.50* 1.38d* l^0" 1.44b° 1.34«f 1.32[ 1.38de 1.24* 0.018 33
9.57» 8.04 9.32«b 9.06 b 8.63° 8.44° 9.53° 9.49 s 9.25 ab 9.36»b 9.28 ab
9.00 8.24 8.88 8.75 8.54
5.9 15.2 4.2 7.0 8.7
0.120 30
Treatments followed by the same letter are not significantly different (P= <0.05).
depression. This may be related to the fact that the RSO foots were considerably higher in erucic acid (42.9%) (Table 6) than any other RSO product. As with chicks, the LEAR gave superior performance compared to the remaining rapeseed products when fed singly. There was a lower level of synergism in poults upon mixing tallow with rapeseed oils or RSO foots as compared with chicks. This is probably due to the fact that the M.E. values of these fats were already very high and thus mixing of the fat products would not be expected to increase the M.E. value to any great extent. The ratios of fatty acids needed for optimum fat absorption in turkey poults is obviously different from that required in the chick. The rapeseed gum fraction also exerted a greater effect on M.E. in the poult than in the chick. In work with young pigs the apparent digestibility of the same samples of degummed RSO and tallow used in these experiments was 9 1 % in each case and there was no synergism in digestibility due to mixing the two fats (Slinger et al.,
1969). It is obvious that there are considerable species differences in fat utilization. Experiment 3. To confirm that one reason for the synergism between RSO or RSO foots and tallow is the low concentration of long chain saturated fatty acids in RSO, an experiment was designed to determine the possible synergistic effect of blending two commercial mixtures of saturated fatty acids with RSO and RSO foots. Mixture A contained 43.7% palmitic acid, 48.9% stearic acid, 3.3% myristic acid and 4% of other fatty acids. Mixture B contained 12% palmitic acid, 80% stearic acid, 2.7% arachidic acid, 2.4% behenic acid, 1.4% lignoceric acid and 1.5% of other fatty acid. In a previous chick experiment mixture A was found to contain 0.63 and mixture B 0.03 kcal./g. of metabolizable energy. Two levels (2.5, 5.0%) of fatty acid mixtures A and B were added to the diets containing RSO and RSO foots. The M.E. values of degummed RSO and RSO foots as affected by mixing with either tallow or saturated fatty acids are presented in Table 4. As in the previous exper-
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Basal Undegummed RSO Degummed RSO Low erucic RSO RSO foots A.V. blend Prime tallow (PT) PT+undegummed RSO PT+degummed RSO PT+low erucic RSO P T + R S O foots PT+A.V. blend
Feed/ Gain
METABOLIZABLE ENERGY OF RAPESEED OILS
149
TABLE 4.—Utilization of rapeseed oil and rapeseed oil foots as influenced by tallow and saturated fatty acid mixtures1 Metabolizable energy Average feed cons.
Average weight gain
Supplement
fe-)
fe.) bod
562" 538 a b 506bai 538 8b ° 5443b 464 d 531»b° 512 bl! 496»d 484 c d 497cd
Sx DF
39
1
511
859*
soa1*"1 543» b
g04bcd 753° 806 b o d 841» b 8 21abc 8 2i»bo 824» b 767 d ° 775ode glCjabo
800M 803bi=d 815 a b l !
14.4 39
11.6
1.68» 1 6Q.bc 1 40" d 1 43 " 1 5e> bcd b 1 62» 1 53bode bode 1 52 ab 1 65 0de 1 46 1 6o* b 1 61* b 1 66» 1 64ab 0.043 39
Calculated from components
Increase
(kcal./g.)
(kcal./g.)
(%)
7.20 b 7.42 b 8.39» 7.06b° 7.48 b 6.10^ 7.42 b 7.37 b 8.02* 6.22d« 6.60«i 6.04« 6. II 8
.— — 7.31 5.72 6.57 5.57 6.50 — 7.28 5.69 6.53 5.54 6.46
Derived
in
M.E.
— — 14.8 23.4 13.8 20.3 14.2 — 10.2 9.3 1.1 9.0 -5.4
0.156 36
Treatments followed by the same letter are not significantly different (P= <0.05).
iments the mixtures of tallow with RSO or
increase in M.E. of RSO was greater with
RSO foots gave M.E. values significantly
the higher level (5%) as compared to the
greater than the arithmetic means of the
lower level (2.5%) of both mixture A and
components.
Supplementation
of
de-
mixture B. The addition of only the higher
gummed RSO with mixture A and mixture B
level (5%) of mixture A and mixture B re-
of saturated fatty acids resulted in an in-
sulted in an increase in the M.E. content of
crease in the M.E. content of the fats. The
RSO foots. In the case of both the RSO
TABLE 5.—Metabolizable energy of rapeseed oil foots as influenced by blending with tallow1 Fat level Basal
Metabolizable energy Average weight gain
Average feed cons.
Feed/ Gain
—
Prime tallow
RSO foots
(%)
(%)
(%)
(g.)
(g-)
100 80 80 80 80 80 80 80
20 16 12 10 8 4 —
— 4 8 10 12 16 20
511" 505" 508" 551 531521" 520> 464
859 804" 756b 807» 775*b 803" 767»»
12.4 21
13.1 21
Sx DF 1
7 9 8 ab
1.68" 1.60»b° 1.50° 1.46" 1.46" 1.51 be 1.54»b0 1.65 ab 0.048 21
Derived
Calculated from components
Increase in M.E.
(kcal./g.)
(kcal./g.)
(%)
— 7.23 7.27 7.28 7.30 7.34 —
— 4.6 9.8 10.2 4.1 4.9
7.20" 7.56b° 7.98" 8.02" 7.60b<= 7.70 b 7.37"° 0.156 18
Treatments followed by the same letter are not significantly different (P= <0.05).
•
—
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Basal Prime tallow Degummed RSO (RSO) RSO+Prime tallow (10:10) RSO+MixtureA(15:5) RSO+Mixture A (17.5:2.5) RSO+Mixture B (15:5) RSO+Mixture B (17.5:2.5) Rapeseed oil foots (RSOF) RSOF+Prime tallow (10:10) RSOF+Mixture A (15:5) RSOF+Mixture A (17.5:2.5) RSOF+MixtureB(15:5) RSOF+Mixture B (17.5:2.5)
Feed/ Gain
150
S. P. LALL AND S. J. SLINGER TABLE 6.—A nalyses of experimental fats Degummed RSO
Low erucic RSO
RSO foots
A.V. blend
Prime tallow
0.94 105 179 0.79 0.07 9.45
1.00 105 177 0.64 0.00 9.38
0.56 112 189 0.66 0.05 9.37
50.00 102 175 1.85 0.85 9.24
69.00 107 187 2.64 1.20 9.15
3.75 49 195 0.44 0.35 9.38
2.5 0.1 1.1 31.4 17.2 8.0 12.4
3.2 0.2 1.5 27.4 18.3 8.1 11.9
—
—
27.2
29.3
and RSO foots it would appear that the synergism brought about by blending with tallow could be accounted for entirely on the basis of the altered fatty acid profile resulting from the addition of long chain saturated fatty acids at a sufficiently high level. Experiment 4. The results of experiment 1 showed a synergistic effect on M.E. of mixing tallow and RSO foots. Because of the practical implications of this finding this experiment was undertaken to determine the proportions of RSO foots and tallow which would give the greatest effect. The increase in M.E. content of the mixtures of 60:40 and 50:50 tallow and RSO foots gave superior growth, feed efficiency and M.E. as compared to other mixtures (Table 5). The 60:40 and 50:50 mixtures of tallow and RSO foots gave ratios of unsaturated to saturated fatty acids of 2.15:1 and 2.62:1 respectively. This would further support the finding of Young (1968) that fats are more efficiently utilized if the ratio of unsaturated to saturated fatty acids is equal to or greater than 1.4 to 1. A 20:80 combination of tallow and RSO foots had a ratio of 5.48:1. As the proportion of
4.0 0.3 2.2 61.3 20.0 9.7 1.1
—
1.2
5.5 0.7 1.8 16.6 15.6 8.7 8.2
9.7 9.3 3.2 33.8 23.0 8.5
—
9.4 3.0
42.9
—
27.0 4.2 20.9 41.4 4.8 1.5
.— — —
RSO foots was increased beyond the 50% level in the mixture the degree of synergism declined. This may be related to the high level of erucic acid in the RSO foots (Table 6) interfering with the absorption of fatty acids, particularly oleic acid, in the manner alluded to earlier. Increasing the ratio of unsaturated to saturated fatty acids much above 2.6:1 appeared to be detrimental. It is of interest that the 50:50 ratio of tallow and RSO foots which produced the best results, gave a ratio of monounsaturated to saturated fatty acids of 2.06:1 which is very close to the recommended ratio for rats as proposed by Hopkins (1955). ACKNOWLEDGEMENTS
The financial assistance of the Rapeseed Association of Canada, Canada Packers Ltd., the National Research Council and the Ontario Department of Agriculture and Food is gratefully acknowledged. REFERENCES Arthur, D., 1970. The determination of chromium in animal feed and excreta by atomic absorption spectrophotometry. Can. Spectroscopy, 15: 1-4.
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Free fatty acids (%) Iodine value Saponification value Unsaponifiables (%) Moisture (%) Gross energy (kcal./g.) Fatty acid composition (%) 16:0 16:1 18:0 18:1 18:2 18:3 20:1 20:5 22:1
Undegummed RSO
METABOLIZABLE ENERGY OF RAPESEED OILS
ques du rat. Biochim. Biophys. Acta 125: 118128. Sell, J. L., and G. C. Hodgson, 1962. Comparative value of dietary rapeseed oil, sunflower seed oil, soybean oil and animal tallow for chickens. J. Nutrition, 76: 113-118. Sheppard, A. J., J. C. Fritz, W. H. Hooper, T. Roberts, W. D. Hubbard, A. R. Prosser and J. W. Boehne, 1971. Crambe and rapeseed oils as energy sources for rats and chicks and some ancillary data on organ weights and body cavity fat deposition. Poultry Sci. 50: 79-84. Sibbald, I. R., and S. J. Slinger, 1963. A biological assay for metabolizable energy in poultry feed ingredients together with findings which demonstrate some of the problems associated with the evaluation of fats. Poultry Sci. 42: 313325. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1961. Factors affecting the metabolizable energy content of poultry feeds. 2. Variability in the M.E. value attributed to samples of tallow and undegummed soybean oil. Poultry Sci. 40: 303-308. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1962. The utilization of a number of fats, fatty materials and mixtures thereof evaluated in terms of metabolizable energy, chick weight gains and gain :feed ratios. Poultry Sci. 4 1 : 4661. Slinger, S. J., S. P. Lall and W. E. Carlson, 1969. Nutritional value of rapeseed oils for poultry and pigs. Proc. Nutr. Conf. for Feed Manufacturers, Univ. of Guelph: 32-40. Steel, R. G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Company, Inc., New York and London. Thomasson, H. J., 1956. The biological value of oils and fats. IV. The rate of intestinal absorption. J. Nutrition, 59: 343-352. Tsang, S. T. L., E. L. Mckee, G. P. Andrews and H. A. Windsor, 1962. The value of rapeseed screening oil in broiler rations. World Poultry Sci. J. 18: 142-146. Young, R. J., 1961. The energy value of fats and fatty acids for chicks. 1. Metabolizable energy. Poultry Sci. 40: 1225-1233. Young, R. J., and R. L. Garrett, 1963. Effect of oleic and linoleic acids on the absorption of saturated fatty acids in the chick. J. Nutrition, 8 1 : 321-329. Young, R. J., 1968. Evaluation of the nutritional value of feed grade fat. Proc. 1968 Arkansas Formula Feed Conference, Fayetteville, Arkansas, 53-71.
Downloaded from http://ps.oxfordjournals.org/ at New York University on May 22, 2015
Artman, N. R., 1964. Interactions of fats and fatty acids as energy sources for the chick. Poultry Sci. 4 3 : 994-1004. Association of Official Agricultural Chemists, 1965. Official Methods of Analysis. 10th Edition, Washington D.C. Beare, J. L., J. A. Campbell, C. G. Youngs and B. M. Craig, 1963. Effects of saturated fat in rats fed rapeseed oil. Can. J. Biochem. Physiol. 4 1 : 605-612. Blakely, R. M., H. I. MacGregor and D. Hanel, 1965. Performance of turkeys on finishing diets containing different fats. Can. J. Anim. Sci. 45: 59-61. Carroll, K. K., 1965. Dietary fat and the fatty acid composition of tissue lipids. J. Amer. Oil Chem. Soc. 42: 516-527. Craig, B. M., C. G. Youngs, J. L. Beare and J. A. Campbell, 1963a. Fatty acid composition and glyceride structure in rats fed rapeseed oil or corn oil. Can. J. Biochem. Physiol. 4 1 : 43-49. Craig, B. M., C. G. Youngs, J. L. Beare and J. A. Campbell, 1963b. Influence of selective and non-selective hydrogenation of rapeseed oil on carcass fat of rats. Can. J. Biochem. Physiol. 41:51-56. Hopkins, C. Y., T. K. Murray and J. A. Campbell, 1955. Optimum ratio of saturated to monounsaturated fatty acids in rat diets. Can. J. Biochem. Physiol. 3 3 : 1047-1054. Joshi, S. K., and J. L. Sell, 1964. Comparative dietary value of soybean oil, sunflower oil, rapeseed oil, and animal tallow for turkey poults. Can. J. Anim. Sci. 44: 34-38. Murray, T. K., J. L. Beare, J. A. Campbell and C. Y. Hopkins, 1958. Further studies on the optimum ratio of saturated to monunsaturated fatty acids in rat diets. Can. J. Biochem. Physiol. 36: 653-657. Renner, R., and F. W. Hill, 1961. Factors affecting the absorbability of saturated fatty acids in the chick. J. Nutrition, 74: 254-258. Rocquelin, G. and J. Lederc, 1969. L'huile de colza riche en acid erucique et l'huile de colza sans acide erucique. II. Utilization digestive comparee chez le rat. Ann. Biol. Anim. Bioch. Biophys. 9: 413-426. Salmon, R. E., 1969a. Soybean verstis rapeseed oil in turkey starter diets. Poultry Sci. 48: 87-93. Salmon, R. E., 1969b. The relative value of rapeseed and soybean oils in chick starter diets. Poultry Sci. 48: 1045-1050. Savary, P., and M. J. Constantin, 1966. Sur la resorption intestinale des chaines eruciques et leur incorporation dans les chylomicrons lymphati-
151
MAREK'S DISEASE IN QUAIL REFERENCES Andrewes, C. H., and R. E. Glover, 1939. A case of neurolymphomatosis in turkey. Vet. Rec. S I : 934. Halliwell, W. H., 1971. Lesions of Marek's disease in a Great Horned Owl. Avian Dis. 15: 49-55. Jungherr, E., 1939. Neurolymphomatosis Phasianorum. J. Amer. Vet. Med. Assn. 94: 49. Papenheimer, M., L. C. Dunn and V. Cone, 1929. Studies on fowl paralysis (Neurolymphomatosis
Gallinarum). Exp. Med. 49: 63-85. Payne, L. N., and P. M. Biggs, 1967. Studies on Marek's disease. II. Pathogenesis. Nat. Cancer Inst. 39: 281-291. Sevoian, M., D. M. Chamberlain, and R. N. Larose, 1963. Avian lymphomatosis. VII. New support for etiologic unity. Proc. Seventeenth Worlds Vet. Cong. 2: 1475. Wight, P. A. L., 1963. Lymphoid leucosis and fowl paralysis in the quail. Vet. Rec. 75: 685-687.
S. P. LALL AND S. J. SLINGER Department of Nutrition, University of Guelph, Guelph, Ontario, Canada (Received for publication April 12, 1972)
ABSTRACT Experiments were carried out with chicks and turkey poults to determine the metabolizable energy content of rapeseed oils and rapeseed oil foots and the effect on energy utilization of blending these oils with tallow and mixtures of saturated fatty acids. In general, low erucic acid rapeseed oil (Oro variety) gave superior growth and feed efficiency and was as high or higher in M.E. value as compared with regular Brassica campestris rapeseed oil. While rapeseed oils and rapeseed oil foots were reasonably well utilized as a source of energy by chicks and poults, there was a synergistic effect in energy utilization when these oils were mixed with tallow. Thus the energy content of the mixture of rapeseed oil and tallow was greater than that anticipated from the fats fed singly. The synergism was less for poults than for chicks, probably because poults utilized rapeseed oils to a greater extent than chicks when fed without mixing. Chicks fed mixtures made up chiefly of palmitic and stearic acids, along with rapeseed oil or rapeseed foots, demonstrated similar synergism in fat utilization to those fed tallow with rapeseed oil. These results confirm and extend previous findings indicating that rapeseed oil is imbalanced in fatty acid make-up for maximum absorption, being too low in the long chain saturated fatty acids, palmitic and stearic. While synergism in energy utilization was also demonstrated when low erucic acid oil was mixed with tallow, the effect was less than with regular Brassica campestris oil. This is probably explained by the fact that the low erucic acid oil is better utilized when fed alone than the regular rapeseed oil. POULTRY SCIENCE 52:
INTRODUCTION
Q
UANTITATIVE data on the utilization of rapeseed oil (RSO) by poultry ate quite limited. Joshi and Sell (1964) reported that inclusion of 5 or 10% RSO in the diet of turkey poults caused a depression in weight gain and feed consumption with the magnitude of depression being in direct proportion to the RSO content of the diet. Metabolizable energy (M.E.) values determined on the total diets indicated that
143-151,
1973
the energy supplied by RSO was as available to poults as that from soybean oil (SBO), sunflower oil or animal tallow. Salmon (1969a) reported that 9% RSO depressed the growth, feed conversion, and dietary M.E. of diets for growing turkeys as compared to 9% SBO; mixtures of RSO with one-third or more of SBO or with less than one-third beef tallow gave equal performance to 9% SBO. However, Blakely et d. (1965) found that 6 or 10% RSO was
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The Metabolizable Energy Content of Rapeseed Oils and Rapeseed Oil Foots and the Effect of Blending with Other Fats
144
S. P. LALL AND S. J. SLINGER
ported for erucic acid, the utilization of low erucic acid RSO (LEAR) was also studied. In view of the findings of Sibbald etal. (1961,1962) andArtman (1964) that mixing SBO and tallow resulted in a greater M.E. than predicted from the arithmetic mean of the two fats fed singly, the present studies were also designed to test the synergistic relationship between tallow and rapeseed oil. Estimates of the M.E. of RSO in previous studies reported in the literature have been based on determining the M.E. of complete diets containing RSO or other oils. While this method permits a rough approximation of the M.E. of RSO as compared to certain other oils it does not permit as accurate an estimate as the quantitative method used here. EXPERIMENTAL MATERIALS AND METHODS
A series of four experiments was conducted to determine the M.E. value of RSO, RSO foots (acidulated soap stocks), tallow and various mixtures of these fat products and fatty acids. The regular RSO was Brassica campestris and was fed in both the crude and degummed state but without futher refining. The LEAR was Oro variety of the Brassica napus species containing 1.2% erucic acid. For the various experiments, male one-day-old White Rock chicks or female Large White turkeys were housed in electrically heated wire-floored battery brooders. The chicks were given a commercial starting ration for a period of 2 weeks preceeding experiment 1 and 1 week in experiments 3 and 4. Thereafter, the birds were weighed, divided into groups having a weight spread of 5 g. and distributed into pens until each pen contained 10 chicks or 8 poults. All experiments were of randomized complete block design with each of the experimental diets allotted to four replicate pens. The birds were fed a
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not growth depressing for 20-24 week-old finishing turkeys. In contrast to the growth depressing effects of RSO reported for poults, Sell and Hodgson (1962) and Tsang et al. (1962) found no such detrimental effect with the chick. Sell and Hodgson (1962) observed that 4 to 8% RSO was as effective as comparable levels of SBO in improving weight gain and efficiency of feed utilization of chicks. However, Salmon (1969b) reported that substitution of different levels of RSO in diets containing 10% total added oil depressed the growth of chicks but that the M.E. content of the diets was approximately the same. Furthermore, Sheppard et al. (1971) reported that chicks fed diets containing 16% RSO showed reduced growth and poorer feed utilization as compared with chicks receiving diets with 16% corn oil. Based on their method of assay rapeseed oil had 67 and 70% of the energy value of corn oil in two experiments. Work with rats indicates that the relatively poor performance on RSO may be due to an imbalance of saturated and monounsaturated fatty acids (Hopkins et al., 1955; Murray et al., 1958) or the relatively low content of palmitic acid (Beare et al., 1963; Craig et al, 1963a, b) in rapeseed oil. Renner and Hill (1961) and Young (1961) showed that palmitic and stearic acids were poorly utilized by chicks when fed alone; however, the absorption was much more rapid when these fatty acids were fed as part of a mixture of fatty acids. Young and Garrett (1963) reported that the presence of oleic acid and to some extent linoleic acid enhanced the absorption of saturated fatty acids. The following studies were undertaken to determine the M.E. content of RSO and rapeseed oil foots (acidulated soap stocks from RSO) for chicks and turkey poults. The same samples were used for both species. Because of the deleterious effects re-
145
METABOLIZABLE ENERGY OF RAPESEED OILS
RESULTS AND DISCUSSION
Experiment 1. The first experiment was
TABLE 1.—Composition of basal diets Basal diets 1 Ingredient
• Chickens
Turkeys
(%)
(%)
27.25 Ground corn Soybean meal (49% protein) 56.00 4.00 Dehydrated alfalfa meal (17% protein) 2.50 Meat meal (50% protein) 2.50 Fish meal (60% protein) 2.50 Dried whey (55% lactose) 2.00 Ground limestone 2.00 Dicalcium phosphate 0.50J Iodized salt 0.75 Vitamin-mineral mix 1
26.00 58.50 2.00 2.50 3.50 2.00 2.00 2.25 0.50s 0.75
Each diet contained 0 . 3 % chromium sesquiox-
ide.
8
Vitamin-mineral mix provided (per kg. of basal diet): vitamin A, 10,080 I.U.; vitamin D 3 , 1,240 I.C.U.; vitamin E, 32 I.U.; menadione sodium bisulfite, 2.2 mg.; riboflavin, 7 mg.; d-calcium pantothenate, 6.2 mg.; niacin, 5.5 mg.; vitamin B12, 0.03 mg.; choline chloride, 188 mg.; manganese, 84 mg.; zinc, 84 mg.; 3-nitro-4^hydroxyphenylarsonic acid, 50 mg.; DL-methionine, 500 mg.; penicillin, 11 mg. 5 Vitamin-mineral mix provided (per kg. of basal diet): vitamin A, 10,080 I.U.; vitamin D 3 , 1,500 I.C.U.; vitamin E, 32 I.U.; menadione sodium bisulfite, 3 mg.; riboflavin, 8 mg.; d-calcium pantothenate, 7.5 mg.; niacin, 60 mg.; vitamin Bis, 0.03 mg.; choline chloride, 225 mg.; manganese, 84 mg.; zinc, 84 mg.; 3-nitro-4-hydroxyphenylarsonic acid, 50 mg.; DL-methionine, 500 mg.; penicillin, 11 mg.
designed to determine the M.E. content of degummed RSO, undegummed RSO, LEAR, RSO foots (acidulated soap stocks from RSO), A.V. blend (a commercial mixture of animal and vegetable fat containing some RSO), prime tallow and a 50:50 mixture of tallow and RSO or RSO foots. Because a sufficient amount of LEAR was not available at the time, the M.E. value for the mixture of tallow and the LEAR was not determined. The M.E. values derived for the fats and fat mixtures on chicks, together with the weight gain, feed consumption and feed: gain data, are presented as means in Table 2. Prime tallow contained significantly less M.E. than any of the oils being tested. The M.E. of undegummed RSO was slightly higher than degummed RSO. However,
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practical corn-soybean diet (Table 1, ration A for chicks, ration B for poults) or the appropriate diet containing 20% of the various fats, fat mixtures or fatty acid mixtures. The fat replaced the diet as a whole. The chicks were given the experimental diets to 4 weeks of age. The turkey poults received the experimental diets from dayold through 3 weeks of age. All diets were supplied ad libitum. During the last 6 days of the experiments, three excreta samples were collected on alternate days from each pen, pooled, frozen, lyophilized and ground in preparation for analyses to permit the determination of M.E. values according to the procedure outlined by Sibbald and Slinger (1963). Both feed and excreta samples were assayed for gross energy using a Parr oxygen bomb calorimeter, nitrogen by the method of Kjeldahl (A.O.A.C, 1965) and chromium sesquioxide using a Techtron atomic absorbtion spectrophotometer (Arthur, 1970). The fatty acid composition of the fats was determined by gas-liquid chromatography. A Barber Colman series 5000 gas chromatograph equipped with dual hydrogen flame ion detectors was used. The stainless steel column was 200 cm. X 2 mm. I.D. and was packed with 85% chromosorb W coated with 15% ethylene glycol adipate; they were operated isothermally at 210°C. The determination of total free fatty acids, unsaponifiables and moisture was accomplished by the procedure of the Association of Official Agricultural Chemists (1965). The data from these experiments were analyzed by the method of analysis of variance and the test of significance was made using Duncan's multiple range test at the 5% probability level as outlined by Steel and Torrie (1960).
146
S. P. LALL AND S. J. SLINGER
TABLE 2.—Fat utilization by the chicken1 Metabolizable energy Supplement
Average feed cons.
(g.)
(g.)
323 374d 387M 4H«b
3771*1 367 d 390 b c d 427» 4Q9ab
403»bo 394bcd 8.2 30
Sx DF 1
693" 638cd 658b° 673*b 648b° 634«> 651 bc 657"° 671*b 656b° 626* 7.8 30
Feed/ Gain
Derived
Calculated from components
Increase in M.E.
(kcal./g.)
(kcal./g.)
—
— —• —
(%) —. •— — — — — —
2.15 1.71" 1.70"b 1.64b° 1.72" 1.73" 1.67ab 1.544 1.64b= 1.63b0 1.59°d
7.99 e 7.89* 8:'71d 7.81= 7.86" 7.12 9.18 a b 9.01b° 9.23" 8.97°
0.025 30
0.065 27
•
—
— — —
7.56 7.50 7.46 7.49
21.4 20.1 23.7 19.8
Treatments followed by the same letter are not significantly different (P= <0.05).
weight gain and feed consumption were = 33-34°C.) and well incorporated into somewhat lower for undegummed RSO bile salt conjugated micellar solutions; than degummed RSO. It would appear that however, it was not as well absorbed as rapeseed gums may contain some factor (s) oleic acid. Rocquelin (1969) found that which reduces feed consumption and approximately 75% of the total fatty acids growth but enhances M.E. recovered from feces of rats fed RSO was The M.E. content of LEAR was signifi- erucic acid which was excreted mainly as cantly higher than that of any other fat free acid or partial glycerides. Since the fed singly. Also weight gain and feed effi- metabolizable energy value of a fat is diciency for chicks fed the LEAR were supe- rectly related to absorption, the superior rior to the other fats. Thomasson (1956) performance of chicks fed LEAR supports reported that RSO is more slowly absorbed the view that the lower utilization of reguthan most other oils because of its high lar RSO may be associated with the erucic erucic acid content. It has been shown that acid. oleic acid, which constitutes 6 1 % of LEAR Although RSO foots and A.V. blend gave fatty acids (Table 6) is much better uti- inferior performance based on weight gain lized than erucic acid. Carroll (1965) indi- and feed efficiency, the M.E. values were cated that in rats fed RSO or erucic acid not significantly different from the other the intestinal wall becomes thickened and rapeseed products. the intestinal mucosa takes on a milky apThe M.E. data indicate that mixtures of pearance due to the presence of emulsified various fats with tallow contained more fats, mainly in the form of triglyceride. avilable energy than the mean of the comThis may be due to slow removal from the ponents. The average increase was about intestinal mucosa of glycerides containing 20% (Table 2, last column) and the differerucic acid. ences were statistically significant. CalcuSavary and Constantin (1966) observed lations showed that mixing tallow and the that erucic acid was liquid at 37°C. (M.P. RSO products enhanced the utilization of
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Basal Undegummed RSO Degummed RSO Low erucic RSO RSO foots A.Vt blend Prime tallow (PT) PT+undegummed RSO PT+degummed RSO P T + R S O foots P T + A . V . blend
Average weight gain
METABOLIZABLE ENERGY OF RAPESEED OILS
acids and the low levels of palmitic and stearic acids in this oil. Young (1968) suggested that fat or fat mixtures are more efficiently utilized if the ratio of unsaturated to saturated fatty acids is equal to or greater than 1.4:1. The ratio with the mixture of 50:50 tallow and rapeseed oil was 2.84:1 which is in agreement with the above recommendations. The increase in M.E. upon blending RSO and tallow is greater than that achieved by mixing tallow and soybean oil (Sibbald et al., 1962). It may be that the diluting effect of tallow on the relatively slowly absorbed erucic acid in RSO is another reason for the marked synergism in M.E. when tallow and RSO are blended. Experiment 2. The second experiment was designed to determine the M.E. content of the same samples of RSO and RSO foots used in the previous trial but using turkey poults. The M.E. values (Table 3) indicate that this species made better use of all fats than did chicks. Some of the oils were metabolized to the extent of 100% or more; the undegummed RSO showed an M.E. value of 9.57 vs. a gross energy of 9.45 thus suggesting synergism between the RSO with the fat in the basal diet. Unlike the chicks, the poults receiving the diets containing added fat consumed significantly less feed and gained significantly less weight than the poults fed the basal ration. The fact that tallow resulted in a lowered feed intake and growth in relation to the basal diet suggests that the diets in which the fats were included contained a surplus of energy in relation to protein. The higher M.E. of the RSO products may have exaggerated this imbalance thus accounting for the poorer growth and feed efficiency in the RSO groups as compared with the poults fed tallow. However, the evidence suggests that some of the RSO products, particularly the RSO foots, caused some growth
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the energy in both the tallow and the RSO products in all cases. For example, if it is assumed that the M.E. value of the RSO products do not change when they are combined with tallow it becomes possible to calculate the increase in M.E. attributable to tallow resulting from the blending, viz.: (2 X kcal. M.E./g. mixed fat)—(M.E./g. RSO product) = M.E./g. tallow. Subtracting the M.E. value obtained when tallow was fed alone from the new value indicates the increase in M.E./g. of tallow. Using this calculation, it was found that mixing tallow with degummed RSO resulted in an increase in M.E. content of tallow of 3.01 kcal./g. which would give the tallow an M.E. value of 10.13 kcal./g. However, the gross energy of the tallow was only 9.38 kcal./g. so that mixing of tallow and RSO must have resulted in an increase in energy utilization in both tallow and RSO. The weight gain, feed consumption and feed efficiency data also provided evidence that synergism occurred within the fat mixtures. Since degummed and undegummed RSO both showed a synergistic response, the presence or absence of gums cannot be considered responsible for the increased utilization. Hopkins (1955) proposed that the poor performance of rats fed RSO was due to an imbalance of saturated and monounsaturated fatty acids. The best performance of rats was observed when the ratio of saturated to monounsaturated fatty acids was 1:2. The calculation of this ratio for rapeseed oil was found to have a value of 1:14. The 50:50 mixture of tallow and rapeseed oil approached the desirable level of 1:2. It may well be that in the chick as in the rat the optimum ratio for fat absorption of saturated to monounsaturated fatty acids is of the order of 1:2. The lack of equilibrium between saturated and monounsaturated fatty acids in RSO is not caused solely by the high level of erucic acid but also by the relatively high levels of oleic and eicosenoic
147
148
s. P.
LALL AND S. J . !SLINGER
TABLE 3.—Fat utilization by the turkey1
Metabolizable energy Supplement
Average weight gain
Average feed cons.
(g-)
(g-)
377 212b° 226*bb° 254» 187° 215 b 264> 224»bo 244ab 222ab0 21Sb° 248»b
550 293 b 305 b b 318> 280b 296b 370" 322»b 326 ab 293b 295b 307b
Sx DF
12.8 33
18.4 33
1
Derived
Calculated from components
Increase in M.E.
(kcal./g.)
(kcal./g.)
(%)
— — — — — — —
— — — — — —
b
1.46» 1.38d« 1.35def 1.26e 1.50* 1.38d* l^0" 1.44b° 1.34«f 1.32[ 1.38de 1.24* 0.018 33
9.57» 8.04 9.32«b 9.06 b 8.63° 8.44° 9.53° 9.49 s 9.25 ab 9.36»b 9.28 ab
9.00 8.24 8.88 8.75 8.54
5.9 15.2 4.2 7.0 8.7
0.120 30
Treatments followed by the same letter are not significantly different (P= <0.05).
depression. This may be related to the fact that the RSO foots were considerably higher in erucic acid (42.9%) (Table 6) than any other RSO product. As with chicks, the LEAR gave superior performance compared to the remaining rapeseed products when fed singly. There was a lower level of synergism in poults upon mixing tallow with rapeseed oils or RSO foots as compared with chicks. This is probably due to the fact that the M.E. values of these fats were already very high and thus mixing of the fat products would not be expected to increase the M.E. value to any great extent. The ratios of fatty acids needed for optimum fat absorption in turkey poults is obviously different from that required in the chick. The rapeseed gum fraction also exerted a greater effect on M.E. in the poult than in the chick. In work with young pigs the apparent digestibility of the same samples of degummed RSO and tallow used in these experiments was 9 1 % in each case and there was no synergism in digestibility due to mixing the two fats (Slinger et al.,
1969). It is obvious that there are considerable species differences in fat utilization. Experiment 3. To confirm that one reason for the synergism between RSO or RSO foots and tallow is the low concentration of long chain saturated fatty acids in RSO, an experiment was designed to determine the possible synergistic effect of blending two commercial mixtures of saturated fatty acids with RSO and RSO foots. Mixture A contained 43.7% palmitic acid, 48.9% stearic acid, 3.3% myristic acid and 4% of other fatty acids. Mixture B contained 12% palmitic acid, 80% stearic acid, 2.7% arachidic acid, 2.4% behenic acid, 1.4% lignoceric acid and 1.5% of other fatty acid. In a previous chick experiment mixture A was found to contain 0.63 and mixture B 0.03 kcal./g. of metabolizable energy. Two levels (2.5, 5.0%) of fatty acid mixtures A and B were added to the diets containing RSO and RSO foots. The M.E. values of degummed RSO and RSO foots as affected by mixing with either tallow or saturated fatty acids are presented in Table 4. As in the previous exper-
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Basal Undegummed RSO Degummed RSO Low erucic RSO RSO foots A.V. blend Prime tallow (PT) PT+undegummed RSO PT+degummed RSO PT+low erucic RSO P T + R S O foots PT+A.V. blend
Feed/ Gain
METABOLIZABLE ENERGY OF RAPESEED OILS
149
TABLE 4.—Utilization of rapeseed oil and rapeseed oil foots as influenced by tallow and saturated fatty acid mixtures1 Metabolizable energy Average feed cons.
Average weight gain
Supplement
fe-)
fe.) bod
562" 538 a b 506bai 538 8b ° 5443b 464 d 531»b° 512 bl! 496»d 484 c d 497cd
Sx DF
39
1
511
859*
soa1*"1 543» b
g04bcd 753° 806 b o d 841» b 8 21abc 8 2i»bo 824» b 767 d ° 775ode glCjabo
800M 803bi=d 815 a b l !
14.4 39
11.6
1.68» 1 6Q.bc 1 40" d 1 43 " 1 5e> bcd b 1 62» 1 53bode bode 1 52 ab 1 65 0de 1 46 1 6o* b 1 61* b 1 66» 1 64ab 0.043 39
Calculated from components
Increase
(kcal./g.)
(kcal./g.)
(%)
7.20 b 7.42 b 8.39» 7.06b° 7.48 b 6.10^ 7.42 b 7.37 b 8.02* 6.22d« 6.60«i 6.04« 6. II 8
.— — 7.31 5.72 6.57 5.57 6.50 — 7.28 5.69 6.53 5.54 6.46
Derived
in
M.E.
— — 14.8 23.4 13.8 20.3 14.2 — 10.2 9.3 1.1 9.0 -5.4
0.156 36
Treatments followed by the same letter are not significantly different (P= <0.05).
iments the mixtures of tallow with RSO or
increase in M.E. of RSO was greater with
RSO foots gave M.E. values significantly
the higher level (5%) as compared to the
greater than the arithmetic means of the
lower level (2.5%) of both mixture A and
components.
Supplementation
of
de-
mixture B. The addition of only the higher
gummed RSO with mixture A and mixture B
level (5%) of mixture A and mixture B re-
of saturated fatty acids resulted in an in-
sulted in an increase in the M.E. content of
crease in the M.E. content of the fats. The
RSO foots. In the case of both the RSO
TABLE 5.—Metabolizable energy of rapeseed oil foots as influenced by blending with tallow1 Fat level Basal
Metabolizable energy Average weight gain
Average feed cons.
Feed/ Gain
—
Prime tallow
RSO foots
(%)
(%)
(%)
(g.)
(g-)
100 80 80 80 80 80 80 80
20 16 12 10 8 4 —
— 4 8 10 12 16 20
511" 505" 508" 551 531521" 520> 464
859 804" 756b 807» 775*b 803" 767»»
12.4 21
13.1 21
Sx DF 1
7 9 8 ab
1.68" 1.60»b° 1.50° 1.46" 1.46" 1.51 be 1.54»b0 1.65 ab 0.048 21
Derived
Calculated from components
Increase in M.E.
(kcal./g.)
(kcal./g.)
(%)
— 7.23 7.27 7.28 7.30 7.34 —
— 4.6 9.8 10.2 4.1 4.9
7.20" 7.56b° 7.98" 8.02" 7.60b<= 7.70 b 7.37"° 0.156 18
Treatments followed by the same letter are not significantly different (P= <0.05).
•
—
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Basal Prime tallow Degummed RSO (RSO) RSO+Prime tallow (10:10) RSO+MixtureA(15:5) RSO+Mixture A (17.5:2.5) RSO+Mixture B (15:5) RSO+Mixture B (17.5:2.5) Rapeseed oil foots (RSOF) RSOF+Prime tallow (10:10) RSOF+Mixture A (15:5) RSOF+Mixture A (17.5:2.5) RSOF+MixtureB(15:5) RSOF+Mixture B (17.5:2.5)
Feed/ Gain
150
S. P. LALL AND S. J. SLINGER TABLE 6.—A nalyses of experimental fats Degummed RSO
Low erucic RSO
RSO foots
A.V. blend
Prime tallow
0.94 105 179 0.79 0.07 9.45
1.00 105 177 0.64 0.00 9.38
0.56 112 189 0.66 0.05 9.37
50.00 102 175 1.85 0.85 9.24
69.00 107 187 2.64 1.20 9.15
3.75 49 195 0.44 0.35 9.38
2.5 0.1 1.1 31.4 17.2 8.0 12.4
3.2 0.2 1.5 27.4 18.3 8.1 11.9
—
—
27.2
29.3
and RSO foots it would appear that the synergism brought about by blending with tallow could be accounted for entirely on the basis of the altered fatty acid profile resulting from the addition of long chain saturated fatty acids at a sufficiently high level. Experiment 4. The results of experiment 1 showed a synergistic effect on M.E. of mixing tallow and RSO foots. Because of the practical implications of this finding this experiment was undertaken to determine the proportions of RSO foots and tallow which would give the greatest effect. The increase in M.E. content of the mixtures of 60:40 and 50:50 tallow and RSO foots gave superior growth, feed efficiency and M.E. as compared to other mixtures (Table 5). The 60:40 and 50:50 mixtures of tallow and RSO foots gave ratios of unsaturated to saturated fatty acids of 2.15:1 and 2.62:1 respectively. This would further support the finding of Young (1968) that fats are more efficiently utilized if the ratio of unsaturated to saturated fatty acids is equal to or greater than 1.4 to 1. A 20:80 combination of tallow and RSO foots had a ratio of 5.48:1. As the proportion of
4.0 0.3 2.2 61.3 20.0 9.7 1.1
—
1.2
5.5 0.7 1.8 16.6 15.6 8.7 8.2
9.7 9.3 3.2 33.8 23.0 8.5
—
9.4 3.0
42.9
—
27.0 4.2 20.9 41.4 4.8 1.5
.— — —
RSO foots was increased beyond the 50% level in the mixture the degree of synergism declined. This may be related to the high level of erucic acid in the RSO foots (Table 6) interfering with the absorption of fatty acids, particularly oleic acid, in the manner alluded to earlier. Increasing the ratio of unsaturated to saturated fatty acids much above 2.6:1 appeared to be detrimental. It is of interest that the 50:50 ratio of tallow and RSO foots which produced the best results, gave a ratio of monounsaturated to saturated fatty acids of 2.06:1 which is very close to the recommended ratio for rats as proposed by Hopkins (1955). ACKNOWLEDGEMENTS
The financial assistance of the Rapeseed Association of Canada, Canada Packers Ltd., the National Research Council and the Ontario Department of Agriculture and Food is gratefully acknowledged. REFERENCES Arthur, D., 1970. The determination of chromium in animal feed and excreta by atomic absorption spectrophotometry. Can. Spectroscopy, 15: 1-4.
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Free fatty acids (%) Iodine value Saponification value Unsaponifiables (%) Moisture (%) Gross energy (kcal./g.) Fatty acid composition (%) 16:0 16:1 18:0 18:1 18:2 18:3 20:1 20:5 22:1
Undegummed RSO
METABOLIZABLE ENERGY OF RAPESEED OILS
ques du rat. Biochim. Biophys. Acta 125: 118128. Sell, J. L., and G. C. Hodgson, 1962. Comparative value of dietary rapeseed oil, sunflower seed oil, soybean oil and animal tallow for chickens. J. Nutrition, 76: 113-118. Sheppard, A. J., J. C. Fritz, W. H. Hooper, T. Roberts, W. D. Hubbard, A. R. Prosser and J. W. Boehne, 1971. Crambe and rapeseed oils as energy sources for rats and chicks and some ancillary data on organ weights and body cavity fat deposition. Poultry Sci. 50: 79-84. Sibbald, I. R., and S. J. Slinger, 1963. A biological assay for metabolizable energy in poultry feed ingredients together with findings which demonstrate some of the problems associated with the evaluation of fats. Poultry Sci. 42: 313325. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1961. Factors affecting the metabolizable energy content of poultry feeds. 2. Variability in the M.E. value attributed to samples of tallow and undegummed soybean oil. Poultry Sci. 40: 303-308. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1962. The utilization of a number of fats, fatty materials and mixtures thereof evaluated in terms of metabolizable energy, chick weight gains and gain :feed ratios. Poultry Sci. 4 1 : 4661. Slinger, S. J., S. P. Lall and W. E. Carlson, 1969. Nutritional value of rapeseed oils for poultry and pigs. Proc. Nutr. Conf. for Feed Manufacturers, Univ. of Guelph: 32-40. Steel, R. G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Company, Inc., New York and London. Thomasson, H. J., 1956. The biological value of oils and fats. IV. The rate of intestinal absorption. J. Nutrition, 59: 343-352. Tsang, S. T. L., E. L. Mckee, G. P. Andrews and H. A. Windsor, 1962. The value of rapeseed screening oil in broiler rations. World Poultry Sci. J. 18: 142-146. Young, R. J., 1961. The energy value of fats and fatty acids for chicks. 1. Metabolizable energy. Poultry Sci. 40: 1225-1233. Young, R. J., and R. L. Garrett, 1963. Effect of oleic and linoleic acids on the absorption of saturated fatty acids in the chick. J. Nutrition, 8 1 : 321-329. Young, R. J., 1968. Evaluation of the nutritional value of feed grade fat. Proc. 1968 Arkansas Formula Feed Conference, Fayetteville, Arkansas, 53-71.
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